Bunker Maintenance and Bunker Renovations

Mark KingoraGolf Course Manager

Golf Course SuperintendentBethesda Country Club

Early bunker maintenance begins in late winter or early spring. A simple depth check is performed to insure that the sand depth is consist at 4 inches throughout each bunker.

A standard soil probe is marked at 4 inches and is used to check the sand depth. During this pre-season check, we typically discover that sand depths vary where the depths are usually less than 4 inches nearest to the green and depths are usually greater than 4 inches in the low areas or farthest away from the green, which is normal due to water flow and normal raking. Any areas of a bunker with excess sand above 4 inches is re-distributed to areas that need additional sand. When sand cannot be moved within the bunkers to maintain the consistent depth, additional new sand is purchased and added as needed.

Bunker Maintenance Process

1. Begins in late winter or early spring2. A simple depth check is performed to insure that the

sand depth is consist at 4 inches throughout each bunker.3. Re-distribute sand or add new sand4. Periodic depth checks

- In heavily concentrated collection areas- After heavy rainfall

5. Maintenance raking is normally 5 times/week6. Grass bunker face mowing is weekly during the growing

season

Factors affecting bunker playability

1. Weather - Rain makes the sand heavy and compacted- Golf balls don’t bury- May appear that sand is too shallow- Dry conditions make the sand fluffy- Golf balls may bury (“fried egg”)- May appear sand is too deep- Normally does not occur because of

irrigation2. Irrigation can have the same affect as rain

Bunker Renovations

1. Bunker Face Re-grassing2. Bunker Sand Replacement

Bunker Face Re-grassing

First, the sand is pulled away from the edge approximately 3-6 feet to give ample room to work. Soil was added to this greenside part of this bunker so that the grass face could be re-built and to reduce the 12 inch depth of sand on the perimeter to a 2 -4 inch taper to reduce the likelihood of plugged balls.

Some of this sand was re-distributed throughout the bunker to maintain a consistent 4” depth.

Sand Splash

Several of the last photos also represents sand buildup from 20 years of bunker shots or “sand splash.”

Three to six feet of the surrounding turf was removed and replaced with zoysiagrass as was specified in Arthur Hills golf course re-design from the early 1990’s. Zoysiagrass was chosen due to it’s ability to withstand drier, sandy soil conditions and shorter mowing heights. Zoysia also has a great brown/tan contrasting color to the white sand and the dark green grasses throughout the golf course in the fall through early spring.

Soil was added to reconstruct the bunker face and edge.

Sod or turf was removed between the bunker and the green and the soil was lowered a foot to its original elevation.

All reconstructed areas are compacted with a vibratory plate tamper to stabilize the soil.

The sand is being redistributed for a consistent 4” depth. The mechanical rake has a plow attachment to aide in this process.

Vibratory Plate Tamper

The vibratory plate tamper is also used on the sand to minimize plugged “fried egg” lies in the bunker.

Completed, number 8 greenside bunkers. These three bunkers were completed in 3 days.

Local RulePlease follow the Local Rule for all renovated bunkers. It is a mandatory drop from all new sod marked with white paint.

It will take 4-6 weeks to establish the turf. Bunkers that are renovated include all on #7 and #8, plus the fairway bunkers on #10 and #15.

Please do not walk up the steep, greenside face of the grass bunker surrounds and keep all traffic on the new sod to a minimum.

Bunker Sand Replacement

• Our most recent Bunker renovations were completed in 2006• Bunker sand usually last 5-7 years• All bunkers have been evaluted• Bunker Sand Replacement Project

– Complete replacement of the sand• Left bunker on #15 green• Left front bunker on #18 green• Possibly the right bunker on #14 green

– Partial replacement of the sand• Remove top contaminated layer• Add new sand to the 4” depth

– Add sand to the 4” depth as needed

• Most bunkers fall into the categories of partial sand replacement or just a need for additional sand.

• Our goal is to extend the life of the bunkers from 5-7 years to 10 -12 years.

• We will evaluate the bunkers annually and may repeat this process in 3 or 4 years to even further extend the life of the bunkers and reduce the need of major bunker reconstruction.